Process and apparatus for producing glass fibrous tubes



TUBES Oct. 27, 1953 J. F. STEPHENS PROCESS AND APPARATUS FOR PRODUCING GLASS FIBROUS Filed May`2, 1949 mm. QW.

Jase/a/z Patented Oct. 27, 1953 2,65 6,87 3 PROCESS AND APPARATUSFOR .PRODUCIN G GLASS FIB Joseph F. Stephens, Kansa Minnesota Mining & Ma

ROUS TUBES- s City, Mo., eassignor to nufacturing Company,

a corporation of Delaware Application May 2, 1949, Serial No. 90,848

(Cl. A1541.7.)

8 Claims.

This invention relates to improvements in a method for producing glass fiber and manufacturing `tubular objects such as pipes therefrom and refers more particularly to a process for forming glass ber reinforced tubes as the ber is spun or drawn.

Pipes or conduits have been made by winding liber glass in the yform of a bat around a mandrel, heating the fibers to incipient fusion or to a temperature sufhcient to cause the `mass `to take IVa permanent set, then `subjecting the wound 'bat to heavy -compacting pressure to reduce the outside diameter to the vdiameter of the finished product. Distinguished from pipes or tubes produced in this fashion are those .made :by the instant method wherein the fibers are spun directly from the spinneret or bushing and wound upon a mandrel and a binder applied prior to or during 4the winding operation. The speed of'rotation ofthe mandrel yor tubular object lon which `the liibers are wound determines the character ofthe fibers since it functions as a wind-opdrum attenuating the fibers as they are drawn from the bushing. To build up layers of the liber the mandrel or tubular object is oscillated longitudinally with respect to the bushing so the fibers are laid up circumferentially upon the cuter periphery of the mandrel in the form `of spiral helices.

An object therefore of the invention is to .provide a method `of producing glass ber and 'applying it as 1t is spun upon the periphery of an elongated rotating object.

Another object is to provide afmethod and aptubular objects of ber glass by winding the fibers as they are spun in the form of cross helices upon the peripheral sur face of a rotating mandrel and reciprocating the mandrel to evenly distribute the fiber in layers.

A further object is to provide a method and apparatus whereby a blnder is applied to the glass liber prior to or during the winding operation, which binder is curable to form an integrated wall structure.

Other and further objects will appear A'from the description which follows.

In the accompanying -drawings which form a part of the specication and are to be read in conjunction therewith, like reference numerals indicate like parts in the various views.

Fig. l is a schematic elevational view apparatus embodying the invention.

Fig, 2 is a View taken along the line 2-2 in Fig. -1 in thedirection of the arrows.

Referring to the drawings, at I'D is shown a of an pcrtionof a forehearth and a liber-forming bushing heated by means Aof gas supplied through pipe II. I2 is `a carriage mounted on flanged wheels I3. Wheels I3 run along `tracks I4 carried `by support members I5. On the carriage I2 are journals I-B which serve as bearings for shaft I1. Mounted on the shaft androtating therewith :is a cylindrical mandrel i8. Attached to the `carriage and oscillatable therewith is `a frame consisting ofan upper horizontal beam I9 positioned beneath the carriage :frame and movable therewith. At the ends of this beam are vertical frame `r11-embers I9a to the lower `end of which is attached an yoffset horizontal frame member I 9b. Attached to the lunderneathsurface of thexlower frame member I 9b vare trip members `Zand 20a.

Carried "between triangular supports I5 which tracks t4 are mounted is a hydraulic cylinder 2l. Within the cylinder is a piston `22 `to which are connected on its opposite ends piston rods 23 'and 28a. The piston rods .are attached at their Iouter yextremities to Athe vertical `frame members I9a.

Hydraulic fluid is supplied tothe cylinder ZI from a hydraulic pump, .not shown, through pipe bushing I0 are designated by the vnumeral 3D.

cation of binder material, suitable valves 32 are interposed in the supply pipes 33.

In operation, glass fibers are drawn in the usual manner from a bushing or spinneret in the lower part of the forehearth lil. Any number of bers, according to the number of holes in the bushing, are drawn simultaneously and wound upon the peripheral surface of the mandre The speed at which the mandrel is rotated by a motor 29 will determine the character of the bers. If relatively small bers are tobe spun, the mandrel will be rotated at high speed. If bers of coarser nature are desired, the mandrel will be rotated at lower speed. In other words, the mandrel functions as a wind-up drum and its speed will determine the character of the bers produced. While rotating at high speed the mandrel is reciprocated or oscillated below the bushing by introduction of hydraulic fluid on opposite sides of piston 22. The functioning of the hydraulic system in reciprocating the carriage l2 is briey as follows. The fluid is introduced through pipe 24 and may be charged rst to the left side of the piston through pipe 25. This moves the piston to the right hand end of the cylinder, discharging uid through pipe 2l, valve 25 and pipe 28 back to the reservoir. Movement of piston 22 to the right hand end of the cylinder will shift the frame I9 and carriage l2 to the right since the frame pistons 23 and 23a. In this position the glass ber is wound onto the leftend of the mandrel. At the end of the stroke, trip member 2e will shift valve arm 25a of Valve 25 to its dotted line position directing the fluid from pipe 2G to pipe 21 thereby converting the latter to a charging line and pipe 2S to a discharging line. In other words when the piston 22 arrives at the outer terminus of its stroke at either end of the cylinder the injection and withdrawal of hydraulic fluid are shifted to opposite ends of the cylinder. To control the of hydraulic iiuid, the abutment of trip members 28 Valve arm 25a.

Describing now the application of the fibers to the mandrel, when arm 25a is in full line position, as in Fig. 1, uid is introduced into the left end of the cylinder 2l through pipe 25. Piston 22 moves frame right while the hydraulic fluid to the right of the piston is discharged from the right end of the cylinder through pipe 21, valve 25 and pipe 28. When the piston reaches the end of its stroke, bers Si) will be wound onto the left end of the mandrel and the stroke will be reversed by trip member 2i) moving arm 25a to its dotted line position. Hydraulic uid now is charged through pipe 2l and is discharged through pipe 26 while the mandrel moves to the left and the bers 3% are distributed upon the periphery of the mandrel in a continuous helix crossing the bers applied to stroke. In this manner successive layers of glass ber are applied circumferentially to the mandrel in successive layers and a tube wall built up to the desired thickness. A binder material such as a resinous substance which may be either valve 25 is manipulatedl by and 2M against thermoplastic or thermosetting is applied to the ber through pipes 3| and 33.

After the tubular object has been formed on the mandrel I8 it may be removed in any suitable manner. The outer periphery of the mandrel, if collapsible, may be readily removed from the interior of the tube or the brous wall of the is attached to the ends of introduction and withfilrawalv i9 and carriage l2 to the the mandrel in the previousv v reinforce the pipe axially or in tube may be cut longitudinally and stripped from the cylindrical surface of the mandrel after which it may be flattened in the form of a mat or again welded to form a tubular object.

Besides producing a tubing or composite pipe by winding a glass ber as it is produced from the bushings directly onto a mandrel in the manner described, it is contemplated as well to a longitudinal direction by separating laid ber. This will be done by first applying to the mandrel on which the laments are helically wound, a layer of glass mat composed oi laments disposed approximately parallel to each other. rihis layer of glass mat is rst applied to the mandrel with laments parallel to the axis of the tubular shape being formed. These longitudinal bers give the resultant product greater axial strength than it would have if composed entirely of circumferentially wound laments in a pattern of opposed helices. By application of alternate layers of unidirectional longitudinal bers and laments there can be built up a much more rigid structure or the longitudinally laid bers may comprise a single inner, outer or intermediate layer with respect to the helically wound filament layers'.

In all cases when the mat isY layed next to the mandrel or when used in alternate layers with the specially wound bers the layers are adhered together by the application of a plastic resin used to compose and unite the helically wound lament and mat in an integral structure.

Mats with approximately parallel ber have been successfully made on a 30" drum. In building up this layer of ber on the drum the continuous laments from the bushing are circumferentially wound about the drum which is transversed back and forth at a relatively slow rate so that the laments are collected in a form of low-pitched helices, the helices in adjacent layers being opposed. As the laments are accumulated, a bonding resin is applied to them by any one of several methods. rihe resin solution or emulsion can be applied to the filament strands as generated from a conventional shoe applicator or sprayed on the lament lay as it is accumulated on the drum; or since the mats being used are quite thin, after the laments have been wound on the drum, the resin may be painted or sprayed on the outside of the mat, All the foregoing methods are continuous to give the mat a bonded integrity.

After the mat laments have been wound to a layer of desired thickness they are cut from the drum the cut being made transversely and axially to the lay of the ber. The circumference of the drum dictates the length of the mat and the length of the drum the width of the mat so formed. rlhus, a drum of between 6 and 'l' in circumference would produce a mat of sufficient length to compose a l0 pipe section, and a drum 50 in width would produce a mat adaptable to the production of a pipe or tubing approximately 8 in diameter. v

In the production of actual pipe the process has been successfully used in building up so called enlarged ends or thickened wall sections adjacent the ends. Such thickened walls may be desirable in order to provide end couplings for the pipe. In forming these thickened wall sections it is necessary to limit the travel distance which the mandrel or drum traverses to cause the lament to wrap only about the area to be thickened and reinforced. Likewise it is possible to include by this method additional layers of the unidirectional mat in the thickened wall section to balance the diametral and axial strength of the reinforced portion.

From |the foregoing it Will be seen that this invention is one Well adapted to attain all of the ends and objects hereinabove set fort-h together with other advantages which are obvious and` Which are inherent to the process and apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is Within the scope of the claims.

As many possible embodiments may be made of rthe invention Without departing from the scope thereof it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. An integrated process of producing glass liber and forming fibrous tubular structures comprising the steps of passing molten glass through the apertures of a bushing to form a plurality of individual fibers, wrapping said fibers circumferentially upon the peripheral surface of an elongated object While rotating said object at a high speed commensurate wi-th the size of the 7 ber to be drawn, applying a binder to the fibers, laying up the fibers upon the rotating object in layers to form a compact unitary structure and removing the object longitudinally from Within the structure to produce an integral fibrous tube.

2. A method as in claim l including the steps of shifting the rotating object longitudinally during the application of the bers whereby the fibers are laid up as cross helices.

3. A method as in claim 1 including the step or longitudinally oscillating the rotating object during application of the fibers whereby the fibers are laid up as cross helices.

4. A method as in claim 1 including the step of curing the binder subsequent to laying up the binder treated bers on the rotating object.

5. In an apparatus for producing tubular objects of glass fiber, the combination with a receptacle containing a batch of molten glass, of a bushing for feeding the glass in a plurality of individual continuous fibers, an oscillating carriage positioned adjacent said bushing adapted to travel in a path transverse to the fiber feed, a mandrel rotatably mounted upon said carriage, drive means mounted on said carriage for rotating said mandrel to Wind the fibers thereupon as they are spun from the bushing, and means for reciprocating the carriage whereby the fibers are applied circumferentially and in successive layers upon the peripheral surface of the mandrel.

ciprocating the piston and carriage.

8. Apparatus as in claim 5 in which the means for reciprocating the carriage comprises a stationary cylinder, a reciprocable piston operatively connected to the carriage, valve controlled ducts for supplying a fluid under pressure to the cylinder on opposite sides of the piston for reciprocating the piston and carriage, and tripping mechanism adapted to. automatically operate the valve to alternately charge pressure fluid to opposite ends of the cylinder.

JOSEPH F. STEPHENS.

References Cited in the iile of this patent UNITED STATES PATENTS Number 

